Sometimes a real piano just won’t work. You might be a cost-conscious parent, wary of snapping up a pricey Steinway for a kid more interested in baseball than bass clefs. Or perhaps you’re going to college, and despite your gifts in spatial reasoning, you won’t be squeezing Dad’s 800-pound Baldwin grand in your 80-square foot dorm room.

Say hello to the digital piano, a far cheaper, much lighter, electronic solution that never goes out of tune. Unlike those plastic 44-key Casio keyboards of the ’90s, today’s top digital pianos feature fully-weighted keys, life-like reverb effects, and beautiful sound quality sampled from the world’s nicest grand pianos. But be careful: there’s a surprisingly large divide between an imitation electronic keyboard and a responsible digital piano. Here’s what to look for:

Number of Keys

Unless you’re a DJ or a digital artist on a keyboard workstation, just stick to 88 keys, the standard number on all pianos. You’ll end up regretting anything else. Back in my 61-key days, I remember making two stacks of music: a pile of simple tunes I could play on 61 keys, and a pile of full-range stuff I’d have to toss out. Don’t make my mistake. Keep the music; throw away the smaller keyboards.

Simple Features

Take a quick look at the speaker set-up (Are there external-facing speakers? Will the piano only make sound with an amplifier?) and inputs/outputs (Is there a headphone jack? Ports compatible with your amp and/or computer?). I once had my credit card in hand, ready to purchase the perfect digital piano, only to realize it had no external speakers—for me, a deal breaker.

Number of Tones/Sounds

Over 600 instruments! Now with 3,000 unique sounds! It’s the advertiser’s favorite thing to mention and the last thing you should worry about. Sure, being able to blast recordings of audience applause or play “Row, Row, Row Your Boat” with police sirens might be fun the first time, but you’ll never use all that nonsense (unless you’re buying for your six-year-old — he’ll pound “Tone #813: Clown Laugh” from now until the day he’s 16). Even some of the best digital pianos will collect excellent samples for the core instruments of the orchestra, then throw in another 900 cheap recordings just so the box can flash a four-digit number on the side. Ignore this.

Some top digital pianos have lots of sounds. Others do not. More sounds don’t lead to higher quality.

Instead, focus on the quality of the dozen basic sounds you will actually use. If you’re lucky enough to be trying a digital piano near a real one, test the bass notes on both. Do they both have a rich, full sound? Try the electric keyboard setting—does it sound whiny and brittle or soft and smooth?

Maximum Polyphony

This fancy term is actually quite simple: It’s the number of individual notes the digital piano can produce at one time. The best way to understand this is to wander over to your local Walmart and find one of those eight-key, Fisher-Price keyboards for $16.99. Play a three-note chord. Chances are, only one of the notes will sound. This keyboard has a maximum polyphony of “one.”

Digital piano polyphonies are like soul mates: You need standards, but you can’t demand perfection. Turn your nose straight up at anything under a 32-note maximum polyphony: 64 is acceptable; 128 is typically best; 256 is probably a marketing gimmick.

Mathematically-inclined readers might be wondering, “Why would I ever need anything over 88, given that a full piano has only 88 keys?” It’s a fair question. If you never play with a sustain pedal, you’ll be fine with that 64-note polyphony. A lot of advanced music, however, requires the player to sustain a whole run of notes up and down the piano. You’ll find you can play 64 notes in quite a hurry, at which point that 64-note limit will kick in, either cutting off the oldest notes or not playing the newest ones. As such, I recommend aiming for 128.

Touch Response

A lot of non-musical parents and first-time pianists love focusing on lights, LED screens, and dials while forgetting about touch response — the single most important part of your digital piano. When players press down on a real piano’s keys, they feel a certain building resistance until the internal hammers strike the piano’s strings. This classic design provides a variety of benefits, from more nuanced dynamics (listen to the pop of Thelonious Monk’s “Round Midnight” vs. the gentle accompaniment of Herbie Hancock on “Blackbird”) to technique (the hammers’ resistance allows a skilled pianist’s fingers to fly effortlessly across the keys).

Throw out this hammer effect and you’ll start relying on lousy technique, playing keys in a wooden, up-and-down manner, while producing music that sounds as flat as James Franco at the 83rd Academy Awards. In general, your three basic categories for touch response include:

This is most typical of digital pianos with few keys (less than 76) and prices under $500. If the manufacturer makes no mention of how the piano feels to the touch, avoid. Also, watch out for pianos featuring “5 volume levels” or an “up/down switch for louder/softer.” This often indicates that the volume can only be changed using that switch, which is a sure sign that the keys have no special touch response. (Better digital pianos do let you turn up and turn down — only they tend to have dials or sliders for more precise control.)

This is the tricky one. Manufacturers love using terms like “touch-sensitive” to crank up the price another $300 for what is actually only a slight improvement. These products will trip over themselves mentioning that “the harder you hit the keys, the louder they sound!” In reality, these products will still feel cheap, and your technique will suffer.

This is what you want. Good digital pianos will do whatever they can to imitate the hammers of a real piano. If you spot the word “weighted,” you’re already on firmer musical ground (unless you see “partially-weighted”…which is a cheaper, less desirable option). Even within this category, there’s still a wide-range of quality, but these products can at least call themselves “pianos” without losing sleep at night.

Bonus: the best digital pianos will even weigh the bass notes just a bit more heavily, which imitates the larger hammers and strings found in a piano’s lower octaves. Little touches like these can really make a difference over time.

With all this in mind, here are three digital pianos worth giving a look:

Real Pianos vs. Digital Pianos

In the end, a decent real piano will nearly always beat a digital piano, so think carefully before dropping $1,500 on a keyboard. If you’re passionate about learning to play, have the space, and can find enough change in your couch cushions, consider the real deal.

Buy a digital piano if…

You don’t have enough space

You need something portable

You perform all over and want something consistent

You like to play late while others are sleeping

Think twice (and buy a real piano) if…

You’re passionate, but still learning basic techniques

You’re prepared to buy a $7,000, digital grand piano

You still don’t care about clown laughter, touch response, and maximum polyphony